JPWO2015182645A1 - Magnetoresistive element, magnetic sensor and current sensor - Google Patents

Abstract

The magnetoresistive element (1) includes a substrate (10) and a laminated body provided above the substrate (10) and in which an antiferromagnetic layer (14) and a ferromagnetic layer are laminated. The ferromagnetic layer includes a first ferromagnetic layer (16) made of Co or an alloy containing Co, and a second ferromagnetic layer (15) made of an alloy containing Ni and Fe, and is antiferromagnetic. The body layer (14) is made of an alloy containing Mn, and the first ferromagnetic layer (16) is provided between the antiferromagnetic layer (14) and the second ferromagnetic layer (15). The first ferromagnetic layer (16) and the antiferromagnetic layer (14) are exchange coupled.

Description

  The present invention relates to a magnetoresistive element, a magnetic sensor, and a current sensor.

  2. Description of the Related Art Conventionally, an AMR (Anisotropic Magneto Resistance) element is known as a magnetoresistive effect element using an anisotropic magnetoresistive effect. The AMR element has a ferromagnetic layer exhibiting an anisotropic magnetoresistance effect.

  In general, the anisotropic magnetoresistive effect is determined by the direction of current flowing through the magnetoresistive element, the magnetization direction of the ferromagnetic layer, and the like. FIG. 20 is a diagram illustrating an example of the direction of current flowing through the magnetoresistive element and the magnetization direction of the ferromagnetic layer. FIG. 21 is a diagram showing output characteristics of a general magnetoresistive element.

As shown in FIG. 21, assuming that the angle at which the moving direction of the current I flowing through the magnetoresistive element intersects the direction of the magnetization M of the ferromagnetic layer is θ, as shown in FIG. The resistance R is expressed as R = R0 + ΔRcos ² θ. Here, R0 is a constant value portion of the resistance, and ΔR is the maximum value of the changing portion. When there is no external magnetic field, the magnetization M is manufactured so as to face the longitudinal direction (easy axis of magnetization), and therefore the characteristics of the AMR element have an even function characteristic with the magnetic field 0 being symmetric.

  AMR elements are often used in magnetic heads and magnetic sensors of magnetic recording media. The AMR element is used in a state in which a magnetoresistive change linearly responds to an external magnetic field by applying a bias magnetic field to the ferromagnetic layer.

  The ferromagnetic layer of the AMR element has a large number of magnetic domains because it includes magnetizations having different directions. For this reason, when the magnetic field is changed, Barkhausen noise is generated when the domain wall moves so as to increase the magnetization. As a method to suppress Barkhausen noise by controlling the magnetization direction of the ferromagnetic layer to make it a single domain, for example, using an exchange coupling magnetic field generated by exchange coupling of the antiferromagnetic layer with the ferromagnetic layer A method to do this has been proposed.

  As a document disclosing a magnetoresistive element using such an exchange coupling magnetic field, for example, Japanese Patent Laid-Open No. 06-076247 (Patent Document 1) is cited. The magnetoresistive element disclosed in Patent Document 1 includes an antiferromagnetic layer made of an alloy containing Ni and Mn and a ferromagnetic layer made of an alloy containing Ni and Fe. The antiferromagnetic layer and the ferromagnetic layer are in direct contact with each other and exchange coupled.

Japanese Patent Laid-Open No. 06-076247

  In the magnetoresistive element disclosed in Patent Document 1, the hysteresis becomes large under a low temperature environment, and the linear response may be deteriorated.

  This invention is made | formed in view of the above problems, and the objective of this invention is providing the magnetoresistive element, magnetic sensor, and current sensor which can reduce a hysteresis.

  As a result of intensive studies to solve the above problems, the inventor has found that there is a gap between an antiferromagnetic layer made of an alloy containing Ni and Mn and a ferromagnetic layer made of an alloy containing Ni and Fe. It has been found that the hysteresis can be reduced particularly on the low temperature side by providing a ferromagnetic layer made of Co or an alloy containing Co.

  The magnetoresistive element based on this invention is provided with the board | substrate and the laminated body which was provided above the said board | substrate and laminated | stacked the antiferromagnetic material layer and the ferromagnetic material layer. The ferromagnetic layer includes a first ferromagnetic layer made of Co or an alloy containing Co, and a second ferromagnetic layer made of an alloy containing Ni and Fe, and the antiferromagnetic layer comprises: The first ferromagnetic layer is made of an alloy containing Mn, and is provided between the antiferromagnetic layer and the second ferromagnetic layer, and the first ferromagnetic layer and the antiferromagnetic material The layers are exchange coupled.

  In the magnetoresistive element according to the present invention, the stacked body includes the antiferromagnetic layer, the first ferromagnetic layer, and the second ferromagnetic layer stacked in order from the substrate side. It is preferable that it is comprised by this.

  In the magnetoresistive element according to the present invention, the second ferromagnetic layer is provided so as to cover the entire first ferromagnetic layer when viewed from the stacking direction of the stacked body. Is preferred. In this case, it is preferable that the magnetoresistive element further includes a plurality of barber pole electrodes provided above the stacked body so as to be separated from each other.

  The magnetoresistive element according to the present invention preferably further includes electrode portions provided at both ends of the laminate. In this case, the magnetization direction of the first ferromagnetic layer fixed by the exchange coupling magnetic field generated between the first ferromagnetic layer and the antiferromagnetic layer and the distance between the electrode portions are shortest. It is preferable that the connecting direction intersect.

  In the magnetoresistive element according to the present invention, the angle at which the magnetization direction of the first ferromagnetic layer fixed by the exchange coupling magnetic field intersects the direction connecting the electrode portions at the shortest is 45. Preferably.

  In the magnetoresistive element according to the present invention, the antiferromagnetic layer includes an alloy containing any one of Ni, Fe, Pd, Pt, and Ir and Mn, Pd, Pt, and Mn. It is preferable to be made of an alloy containing Ni or an alloy containing Cr, Pt and Mn.

  The magnetoresistive element according to the present invention may further include a plurality of electrode portions. In this case, it is preferable that a plurality of the laminated bodies are provided. Further, in this case, the magnetoresistive element includes a plurality of stacked bodies arranged in parallel so that the magnetization directions are aligned, and the ends of the stacked bodies where the plurality of electrode portions are adjacent to each other. It is preferable to form a meander by alternately connecting.

  In the magnetoresistive element according to the present invention, the laminated body may include a portion formed in a meander shape so that the magnetization directions are aligned.

  In the magnetoresistive element according to the present invention, the portion formed in the meander shape alternately connects a plurality of linear portions arranged in parallel and the ends of the linear portions adjacent to each other. It is preferable to be configured by a plurality of folded portions. In this case, it is preferable that a conductive layer having a lower electrical resistance than the ferromagnetic layer is provided on each of the plurality of folded portions.

The magnetic sensor based on this invention is equipped with the said magnetoresistive element.
A current sensor according to the present invention includes a bus bar through which a current to be measured flows, and the magnetic sensor.

  According to the present invention, it is possible to provide a magnetoresistive element, a magnetic sensor, and a current sensor that can reduce hysteresis.

1 is a schematic cross-sectional view of a magnetoresistive element according to a first embodiment. It is a top view which shows the positional relationship of the barber pole electrode with which the magnetoresistive element shown in FIG. 1 is equipped, and a laminated body. FIG. 2 is a cross-sectional view schematically showing a state where the antiferromagnetic layer and the ferromagnetic layer shown in FIG. 1 are exchange coupled. It is a figure which shows the relationship between the magnetic resistance of the magnetoresistive element shown in FIG. 1, and a magnetic field. It is a top view of the magnetic sensor comprised using the magnetoresistive element shown in FIG. It is a figure which shows the result of the composition analysis in the depth direction of the magnetoresistive element in a comparative example. It is a figure which shows the relationship between the bridge voltage change rate of a magnetic sensor which comprises the magnetoresistive element in a comparative example, and a magnetic field. It is a figure which shows the result of the composition analysis in the depth direction of the magnetoresistive element based on an Example. It is a figure which shows the relationship between the bridge voltage change rate of a magnetic sensor which comprises the magnetoresistive element based on an Example, and a magnetic field. It is a figure which shows the relationship between the hysteresis of the magnetoresistive element which concerns on a comparative example, and an Example, and temperature. 6 is a schematic cross-sectional view of a magnetoresistive element according to Embodiment 2. FIG. FIG. 12 is a plan view showing a magnetization direction of a ferromagnetic layer fixed by an exchange coupling magnetic field from an antiferromagnetic layer and a direction connecting the electrodes at the shortest in the magnetoresistive element shown in FIG. 11. It is a top view of the magnetic sensor comprised using multiple magnetoresistive elements shown in FIG. It is a top view which shows the modification of the magnetic sensor shown in FIG. FIG. 6 is a schematic diagram showing a current sensor according to a third embodiment. It is a figure which shows typically the magnetic field which generate | occur | produces in sectional drawing seen from the XVI-XVI line arrow direction shown in FIG. 6 is a schematic cross-sectional view of a magnetoresistive element according to Embodiment 4. FIG. FIG. 10 is a plan view of a magnetic sensor according to a fifth embodiment. FIG. 10 is a plan view of a magnetic sensor according to a sixth embodiment. It is a figure which shows an example of the direction of the electric current which flows through a magnetoresistive element, and the magnetization direction of a ferromagnetic material layer. It is a figure which shows the output characteristic of a general magnetoresistive element.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments, the same or common parts are denoted by the same reference numerals in the drawings, and description thereof will not be repeated.

(Embodiment 1)
FIG. 1 is a schematic cross-sectional view of the magnetoresistive element according to the present embodiment. FIG. 2 is a plan view showing the positional relationship between the barber pole electrode provided in the magnetoresistive element shown in FIG. 1 and the laminated body. With reference to FIG. 1 and FIG. 2, the magnetoresistive element 1 which concerns on this Embodiment is demonstrated.

  As shown in FIG. 1, the magnetoresistive element 1 includes a substrate 10, an insulating layer 11, a stacked body 12, a plurality of barber pole electrodes 17, a pair of electrode portions 18, and a protective layer 19.

  As the substrate 10, for example, a silicon substrate is used. Further, as the substrate 10, an insulating substrate such as a glass substrate or a plastic substrate may be used. In this case, the insulating layer 11 can be omitted.

The insulating layer 11 is provided so as to cover the entire main surface of the substrate 10. For example, a silicon oxide film (SiO ₂ film) or an aluminum oxide film (Al ₂ O ₃ ) is used for the insulating layer 11. The insulating layer 11 is formed by, for example, a CVD method or the like.

  The laminated body 12 has a rectangular shape, for example. The stacked body 12 is provided on the insulating layer 11. The stacked body 12 includes an underlayer 13, an antiferromagnetic material layer 14, and a ferromagnetic material layer 20. As the underlayer 13, a (111) plane parallel to the interface of one metal film made of a metal such as Ta, W, Mo, Cr, Ti, or Zr, or a face-centered cubic crystal and an antiferromagnetic material layer 14. A metal film made of a metal or alloy in which is preferentially oriented (for example, Ni, Au, Ag, Cu, Pt, Ni—Fe, Co—Fe, etc.), and a laminated film in which these metal films are laminated Used. The underlayer 13 is provided on the insulating layer 11. The underlayer 13 is provided for appropriately growing the crystal of the antiferromagnetic material layer 14. The underlayer 13 can be omitted if the crystal of the antiferromagnetic material layer 14 can be grown appropriately.

  The antiferromagnetic material layer 14 is provided above the substrate 10. Specifically, the antiferromagnetic material layer 14 is provided on the underlayer 13. When the underlayer 13 is omitted as described above, the antiferromagnetic material layer 14 is provided on the insulating layer 11.

  The antiferromagnetic material layer 14 includes an alloy containing any one element of Ni, Fe, Pd, Pt, and Ir and Mn, an alloy containing Pd, Pt, and Mn, or Cr, Pt, and Mn. It consists of an alloy containing Mn such as an alloy containing. Since these alloys have a high blocking temperature, the exchange coupling magnetic field does not disappear up to a high temperature. For this reason, the magnetoresistive element 1 can be operated stably.

  An alloy containing Fe and Mn, an alloy containing Pt and Mn, an alloy containing Ir and Mn, and an alloy containing Cr, Pt and Mn are irregular alloys depending on the composition. No heat treatment (heat treatment for ordering the crystal structure) is required. For this reason, when these alloys are employed as the antiferromagnetic material layer 14, the manufacturing process can be simplified.

  The ferromagnetic layer 20 includes a first ferromagnetic layer 16 and a second ferromagnetic layer 15. The first ferromagnetic layer 16 is provided on the antiferromagnetic layer 14 so as to cover the entire main surface of the antiferromagnetic layer 14 located on the side opposite to the side on which the substrate 10 is located. The first ferromagnetic layer 16 is provided between the antiferromagnetic layer 14 and the second ferromagnetic layer 15. The first ferromagnetic layer 16 is made of, for example, Co or an alloy containing Co.

  The second ferromagnetic layer 15 is provided so as to cover the entire first ferromagnetic layer 16 when viewed from the stacking direction of the stacked body 12. Specifically, the second ferromagnetic layer 15 is formed on the first ferromagnetic layer 16 so as to cover the entire main surface of the first ferromagnetic layer 16 located on the side opposite to the side on which the substrate 10 is located. Is provided.

The second ferromagnetic layer 15 is made of a material that produces an anisotropic magnetoresistance effect, such as an alloy containing Ni and Fe or an alloy containing Ni and Co. Since an alloy containing Ni and Fe has a small coercive force, hysteresis can be reduced. In particular, Ni ₈₀ Fe ₂₀ or an alloy containing Ni and Fe having a composition close to Ni ₈₀ Fe ₂₀ has a cubic crystal magnetic anisotropy of approximately 0 erg / cm ³ . A material having a magnetocrystalline anisotropy of 0 erg / cm ³ is isotropic because there is no easy magnetization axis or difficult magnetization axis due to magnetocrystalline anisotropy. In addition, in an alloy containing Ni and Fe having the above composition and a composition close thereto, the magnetostriction is almost zero, so that the magnetic anisotropy induced magnetoelastically by the strain of the crystal is small. In addition, since an alloy including Ni and Fe can easily induce a macroscopic easy axis of magnetization throughout the thin film by heat treatment in a magnetic field, the direction of the easy axis of magnetization throughout the thin film is designed. It becomes easy.

  The plurality of barber pole electrodes 17 are provided above the stacked body 12. Specifically, the plurality of barber pole electrodes 17 are provided on the second ferromagnetic layer 15 so as to be separated from each other. The plurality of barber pole electrodes 17 are provided so as to be inclined by 45 ° with respect to the longitudinal direction of the laminate 12. As the barber pole electrode 17, a metal having good electrical conductivity such as Al is used. In order to improve the adhesion between the barber pole electrode 17 and the second ferromagnetic layer 15, an adhesion layer made of Ti or the like may be provided between the barber pole electrode 17 and the second ferromagnetic layer 15. .

  The laminate 12 is provided so that the magnetization directions of the first ferromagnetic layer 16 and the second ferromagnetic layer 15 coincide with the longitudinal direction of the laminate 12 when there is no external magnetic field. For this reason, the angle at which the direction of the detection current I flowing between the two adjacent barber pole electrodes 17 in the shortest and the magnetization direction of the second ferromagnetic layer 15 intersect is 45 °. The magnetization directions of the first ferromagnetic layer 16 and the second ferromagnetic layer 15 are fixed in the longitudinal direction of the multilayer body 12 by an exchange coupling magnetic field that acts from the antiferromagnetic layer 14.

  In setting the magnetization direction of the second ferromagnetic layer 15 in this manner, first, the underlayer 13 to the second ferromagnetic layer 15 are formed using a vacuum deposition method, a sputtering method, or the like. Subsequently, by performing heat treatment while applying a magnetic field, an exchange coupling magnetic field is obtained between the first ferromagnetic layer 16 and the antiferromagnetic layer 14, and the first ferromagnetic layer 16 and the second ferromagnetic material are obtained. The magnetization direction of the layer 15 is fixed in the direction of the magnetic field.

  Further, when the magnetic layer is applied from the underlayer 13 to the second ferromagnetic layer 15 using a vacuum deposition method, a sputtering method, or the like, if the antiferromagnetic layer 14 is an irregular alloy, the first ferromagnetic Since the magnetization directions of the body layer 16 and the second ferromagnetic layer 15 are fixed in the direction of the magnetic field by the exchange coupling magnetic field between the first ferromagnetic layer 16 and the antiferromagnetic layer 14, an exchange coupling occurs. No heat treatment is required. In order to obtain a sufficiently large exchange coupling magnetic field, after the stacked body 12 is formed, heat treatment may be performed while applying a magnetic field in the same direction as the magnetic field applied during the formation.

  When the antiferromagnetic layer 14 is an ordered alloy, after the stacked body 12 is formed, a heat treatment is performed while applying a magnetic field, so that the first ferromagnetic layer 16 and the antiferromagnetic layer 14 are separated. Thus, an exchange coupling magnetic field is obtained, and the magnetization directions of the first ferromagnetic layer 16 and the second ferromagnetic layer 15 are fixed to the direction of the magnetic field. The direction of the applied magnetic field is better to be the same direction as the magnetic field applied during formation. Next, the multilayer body 12 is patterned into a rectangular shape so that the magnetization direction of the second ferromagnetic layer 15 and the longitudinal direction of the multilayer body 12 coincide.

  The pair of electrode portions 18 are provided so as to sandwich the plurality of barber pole electrodes 17. The pair of electrode portions 18 are provided at both ends of the multilayer body 12 in the direction in which the plurality of barber pole electrodes 17 are arranged (longitudinal direction of the multilayer body 12). Specifically, the pair of electrode portions 18 are provided so as to cover the upper surface of the second ferromagnetic layer 15, the side surface of the stacked body 12 in the direction in which the barber pole electrodes 17 are arranged, and the end of the uppermost layer. Yes. The electrode portion 18 is made of a metal material having good electrical conductivity such as Al. In order to improve the adhesion between the electrode portion 18 and the second ferromagnetic layer 15, an adhesion layer made of Ti or the like may be provided between the electrode portion 18 and the second ferromagnetic layer 15. .

The protective layer 19 is provided so as to cover the multilayer body 12, the plurality of barber pole electrodes 17, and the pair of electrode portions 18. The protective layer 19 is provided with a contact hole 19a so that a part of the pair of electrode portions 18 is exposed. The protective layer 19 is made of, for example, a silicon oxide film (SiO ₂ ), and is provided to prevent the second ferromagnetic layer 15 and the like from being oxidized or corroded. Note that the protective layer 19 may not be provided.

  FIG. 3 is a cross-sectional view schematically showing a state where the antiferromagnetic layer and the ferromagnetic layer shown in FIG. 1 are exchange coupled. With reference to FIG. 3, a state where the antiferromagnetic material layer 14 and the second ferromagnetic material layer 15 are exchange-coupled will be described.

  As shown in FIG. 3, the antiferromagnetic layer 14 is provided over the entire lower surface of the second ferromagnetic layer 15, so that the exchange coupling magnetic field is generated by the first ferromagnetic layer 16 and the second ferromagnetic layer. 15 acts on the whole. Thereby, the magnetization directions of the first ferromagnetic layer 16 and the second ferromagnetic layer 15 can be aligned in one direction. That is, the first ferromagnetic layer 16 and the second ferromagnetic layer 15 can be made into a single magnetic domain.

  Further, by providing the first ferromagnetic layer 16 and adjusting the magnitude of the exchange coupling magnetic field, it is possible to adjust the range of the linearly responsive region. Thereby, the freedom degree of design of an input dynamic range can be enlarged.

  For example, the magnitude of the exchange coupling magnetic field generated between the first ferromagnetic layer 16 and the antiferromagnetic layer 14 is such that the second ferromagnetic layer 15 is laminated directly on the antiferromagnetic layer 14. In addition, it is preferable that the magnitude of the exchange coupling magnetic field generated between the antiferromagnetic layer 14 and the second ferromagnetic layer 15 is larger. In this case, by providing the first ferromagnetic layer 16, the magnitude of the exchange coupling magnetic field that acts on the second ferromagnetic layer 15 from the antiferromagnetic layer 14 can be increased. Thereby, the range of the region which can respond linearly can be expanded.

  The magnitude of the exchange coupling magnetic field can be adjusted, for example, by the film thicknesses of the first ferromagnetic layer 16 and the second ferromagnetic layer 15. By reducing the film thickness of the first ferromagnetic layer 16 and the second ferromagnetic layer 15, the magnitude of the exchange coupling magnetic field is increased.

  FIG. 4 is a diagram showing the relationship between the magnetic resistance and the magnetic field of the magnetoresistive element shown in FIG. With reference to FIG. 4, the relationship between the magnetic resistance of the magnetoresistive element 1 and a magnetic field is demonstrated.

  In the present embodiment, the plurality of barber pole electrodes 17 are provided on the second ferromagnetic layer 15. Since the electric resistance of the second ferromagnetic layer 15 is smaller than the electric resistance of the antiferromagnetic layer 14, the detected current flowing from the electrode part 18 on one end side to the electrode part 18 on the other end side is the second strong It mainly flows through the magnetic layer 15 and the barber pole electrode 17. At this time, the direction of the detection current flowing through the second ferromagnetic layer 15 can be reliably tilted in the direction connecting the adjacent barber pole electrodes 17 in the shortest distance. By setting the angle at which the direction of the detection current I flowing between the two adjacent barber pole electrodes 17 in the shortest and the direction of the magnetization easy axis M of the second ferromagnetic layer 15 intersect is 45 °, FIG. A good linearly responding region as shown in FIG.

  In general, in order to generate exchange coupling or to obtain a sufficiently large exchange coupling magnetic field, the second ferromagnetic layer 15 and the protective layer 19 are formed from the underlayer 13 using a vacuum deposition method, a sputtering method, or the like. After forming, heat treatment is performed while applying a magnetic field. When an alloy containing Mn is employed as the antiferromagnetic material layer, Mn in the antiferromagnetic material layer 14 may diffuse into the second ferromagnetic material layer 15 during the heat treatment. When Mn diffuses into the second ferromagnetic layer, the magnetic moment of the magnetoresistive element may be reduced or the performance may be deteriorated.

  Here, in the present embodiment, by providing the first ferromagnetic layer 16 made of Co or an alloy containing Co, Mn contained in the antiferromagnetic layer 14 is second during the heat treatment in the manufacturing process. Diffusion to the ferromagnetic layer 15 can be prevented. Thereby, even when a magnetoresistive element is used in a low temperature environment, a hysteresis can be reduced. Further, when a ferromagnetic layer containing Co or CoFe is formed between the underlayer 13 and the antiferromagnetic layer 14, Mn diffusion from the antiferromagnetic layer 14 to the underlayer 13 is reduced. And reliability can be further improved.

  Further, since the ferromagnetic layer 20 is provided on the antiferromagnetic layer 14 so as to cover the entire main surface of the antiferromagnetic layer 14, the ferromagnetic layer 20 can be made into a single magnetic domain. . Thereby, Barkhausen noise can be suppressed. Furthermore, in order to move the magnetization of the second ferromagnetic layer 15 by fixing the magnetization direction of the second ferromagnetic layer 15 in one direction by the exchange coupling magnetic field from the antiferromagnetic layer 14, A larger magnetic field is required. Thereby, even when a large magnetic field is applied, the magnetoresistive element 1 is not magnetically saturated, and the region that responds linearly can be expanded.

(Magnetic sensor)
FIG. 5 is a plan view of a magnetic sensor constituted by using a plurality of magnetoresistive elements shown in FIG. With reference to FIG. 5, a magnetic sensor 100 configured by using a plurality of magnetoresistive elements shown in FIG. 1 will be described.

  As shown in FIG. 5, the magnetic sensor 100 is provided by configuring a full bridge circuit using four magnetoresistive elements 1A, 1B, 1C, and 1D. One end of the magnetoresistive element 1A is electrically connected to an electrode pad P1 for taking out the output voltage Vout2 through the wiring pattern 3A. The other end side of the magnetoresistive element 1A is electrically connected to an electrode pad P3 for applying the power supply voltage Vcc via the wiring pattern 3B. One end of the magnetoresistive element 1D is electrically connected to the electrode pad P1 through the wiring pattern 3A. The other end side of the magnetoresistive element 1D is electrically connected to the electrode pad P4 connected to the ground via the wiring pattern 3D.

  One end of the magnetoresistive element 1B is electrically connected to an electrode pad P2 for taking out the output voltage Vout1 through the wiring pattern 3C. The other end of the magnetoresistive element 1B is electrically connected to the electrode pad P3 via the wiring pattern 3B. One end of the magnetoresistive element 1C is electrically connected to the electrode pad P2 via the wiring pattern 3C. The other end side of the magnetoresistive element 1C is connected to the electrode pad P4 via the wiring pattern 3D.

  The magnetoresistive elements 1A, 1B, 1C, 1D are arranged so that their magnetization directions are parallel to each other. The extending direction of the barber pole electrode in the magnetoresistive elements 1A and 1C intersects the extending direction of the barber pole electrode in the magnetoresistive elements 1B and 1D.

  The extending directions of the barber pole electrodes in the magnetoresistive elements 1A and 1C are parallel to each other. The barber pole electrodes in the magnetoresistive elements 1A and 1C are inclined so as to move away from the magnetoresistive elements 1D and 1B from the inside toward the outside.

  The extending directions of the barber pole electrodes in the magnetoresistive elements 1B and 1D are parallel to each other. The barber pole electrodes in the magnetoresistive elements 1B and 1D are inclined so as to be separated from the magnetoresistive elements 1C and 1A from the inside toward the outside.

  The magnetoresistive elements 1A and 1D are connected in series via the wiring patterns 3B, 3A and 3D and the electrode pads P3, P1 and P4, thereby forming a first series circuit (half bridge circuit). The magnetoresistive elements 1B and 1C are connected in series via the wiring patterns 3B, 3C and 3D and the electrode pads P3, P2 and P4, thereby forming a second series circuit (half bridge circuit). The first series circuit (half-bridge circuit) and the second series circuit (half-bridge circuit) are connected in parallel via the electrode pads P3 and P4, thereby forming a full bridge circuit. The magnetoresistive elements 1A and 1C have a positive output property, and the magnetoresistive elements 1B and 1D have a negative output property.

  When the power supply voltage Vcc is applied between the electrode pad P3 and the electrode pad P4, output voltages Vout2 and Vout1 are extracted from the electrode pad P1 and the electrode pad P2 according to the magnetic field strength. The output voltages Vout2 and Vout1 are differentially amplified through a differential amplifier (not shown).

  With this configuration, Mn diffusion from the antiferromagnetic material layer 15 to the second ferromagnetic material layer 15 is suppressed during the manufacture of the magnetoresistive element and the magnetic sensor, thereby reducing hysteresis even in a low temperature environment. be able to. Further, by configuring the bridge circuit, it is possible to improve resistance to changes in the external environment such as temperature.

(Verification experiment)
The conditions and results of a verification experiment conducted to verify the effects of the present invention will be described with reference to comparative examples and examples. The magnetoresistive element in the comparative example is one in which the first ferromagnetic layer is not provided and the second ferromagnetic layer is provided directly on the antiferromagnetic layer. The magnetoresistive element according to the first embodiment is used as the magnetoresistive element according to the example.

  In the comparative example and the example, the composition from the upper layer (surface layer) to the lower layer is analyzed using TEM-EDX for the cross section of the stacked body along the stacking direction. In the magnetoresistive element in the comparative example, the protective layer is not provided on the stacked body 12, and in the example, the protective layer is provided on the stacked body 12. Further, a bridge voltage is generated based on output voltages Vout2 and Vout1 output from the electrode pad P1 and the electrode pad P2 while changing the magnetic field by using a magnetic sensor including a plurality of magnetoresistive elements according to the comparative example and the example. The rate of change is measured.

  FIG. 6 is a diagram showing the result of composition analysis in the depth direction of the magnetoresistive element in the comparative example. FIG. 7 is a diagram illustrating the relationship between the bridge voltage change rate and the magnetic field of the magnetic sensor including the magnetoresistive element in the comparative example. With reference to FIG. 6 and FIG. 7, the composition analysis result in the depth direction of the magnetoresistive element in the comparative example, and the relationship between the bridge voltage change rate and the magnetic field will be described.

In the magnetoresistive element in the comparative example, as a laminated body, a laminated body (Si / SiO ₂ / Ta / Ni—Fe /), in which an underlayer, an antiferromagnetic layer, and a ferromagnetic layer are laminated in this order from the substrate side. Ni-Mn / Ni-Fe) is used. The Si / SiO ₂ described above is a substrate and an insulating layer and is not included in the stacked body. In the comparative example, a laminated film in which an alloy containing Ni and Fe is laminated on a Ta film is used as the base layer 13. An alloy containing Ni and Mn is used as the antiferromagnetic material layer. An alloy containing Ni and Fe is used as the ferromagnetic layer. In the underlayer, the thickness of the Ta film is 2 nm, and the thickness of the alloy layer containing Ni and Fe is 5 nm. In the antiferromagnetic material layer, the thickness of the alloy layer containing Ni and Mn is 40 nm. The thickness of the alloy layer containing Ni and Fe as the ferromagnetic layer is 30 nm.

  As shown in FIG. 6, in the magnetoresistive element in the comparative example, the peak of Mn is confirmed at a position where the depth from the surface layer of the laminated body is several nanometers. At the position where the depth from the surface layer of the laminate is 10 nm to 30 nm, Fe and Ni which are elements constituting the ferromagnetic layer are mainly confirmed. In the position where the depth from the surface layer of the laminate is 40 nm to 70 nm, Ni and Mn which are elements constituting the antiferromagnetic material layer are mainly confirmed. At a position where the depth from the surface layer of the laminate is about 75 nm, Fe and Ni which are elements constituting a part of the underlayer are mainly confirmed. At the position where the depth from the surface layer of the laminate is about 80 nm, a peak of Ta which is an element constituting the underlayer is confirmed. Furthermore, Si, which is an element constituting the insulating layer, is mainly confirmed at a position after 80 nm from the surface layer of the stacked body. Thus, in the magnetoresistive element in the comparative example, Mn is diffused in the upper layer of the ferromagnetic layer 15.

  As shown in FIG. 7, in the magnetoresistive element in the comparative example, the bridge voltage change rate exhibits linearity in the range of −6 [mT] to 6 [mT].

  FIG. 8 is a diagram illustrating a result of composition analysis in the depth direction of the magnetoresistive element according to the example. FIG. 9 is a diagram illustrating the relationship between the bridge voltage change rate and the magnetic field of the magnetic sensor including the magnetoresistive element according to the example. With reference to FIG. 8 and FIG. 9, the composition analysis result in the depth direction of the magnetoresistive element according to the example, and the relationship between the bridge voltage change rate and the magnetic field will be described.

In the magnetoresistive element according to the example, the laminated body 12 is laminated in the order of the base layer 13, the antiferromagnetic layer 14, the first ferromagnetic layer 16, and the second ferromagnetic layer 15 in this order from the substrate 10 side. is used laminate was allowed to _{(Si / SiO 2 / Ta /} Ni-Fe / Ni-Mn / Co-Fe / Ni-Fe). The Si / SiO ₂ described above is a substrate and an insulating layer and is not included in the stacked body. In the embodiment, a laminated film in which an alloy containing Ni and Fe is laminated on a Ta film is used as the base layer 13. An alloy containing Ni and Mn is used as the antiferromagnetic material layer 14. An alloy containing Co and Fe is used as the first ferromagnetic layer 16, and an alloy containing Ni and Fe is used as the second ferromagnetic layer 15.

  In the underlayer 13, the thickness of the Ta film is 2 nm, and the thickness of the alloy layer containing Ni and Fe is 5 nm. In the antiferromagnetic material layer 14, the thickness of the alloy layer containing Ni and Mn is 40 nm. In the first ferromagnetic layer 16, the thickness of the alloy layer containing Co and Fe is 3 nm. In the second ferromagnetic layer 15, the thickness of the alloy layer containing Ni and Fe is 30 nm.

  As shown in FIG. 8, in the magnetoresistive element according to the example, the depth from the surface layer (upper layer of the protective layer 19) of the stacked body 12 provided with the protective layer 19 is several nm. Si which is an element constituting the protective layer 19 is confirmed. At a position where the depth from the upper layer of the protective layer 19 is from several nm to approximately 37 nm, Fe and Ni that are elements constituting the second ferromagnetic layer 15 are mainly confirmed. At the position where the depth from the upper layer of the protective layer 19 is approximately 40 nm, a peak of Co which is a kind of element constituting the first ferromagnetic layer 16 is confirmed.

  Further, at the position where the depth from the upper layer of the protective layer 19 is about 45 nm to about 77 nm, Ni and Mn which are elements constituting the antiferromagnetic material layer 14 are mainly confirmed. At a position where the depth from the upper layer of the protective layer 19 is approximately 80 nm, Fe and Ni that are elements constituting a part of the underlayer 13 are mainly confirmed. At the position where the depth from the upper layer of the protective layer 19 is about 87 nm, the peak of Ta which is an element constituting a part of the underlayer 13 is mainly confirmed. Further, Si, which is an element constituting the insulating layer 11, is mainly confirmed at a position of about 87 nm or more from the upper layer of the protective layer 19. Thus, in the magnetoresistive element according to the example, Mn diffusion from the antiferromagnetic layer 14 to the second ferromagnetic layer 15 is suppressed as compared with the magnetoresistive element in the comparative example. Yes. Since heat treatment is performed in the process before forming the protective layer 19, the presence or absence of the protective film does not affect the diffusion of Mn.

  As shown in FIG. 9, in the magnetic sensor including the magnetoresistive element according to the example, the bridge voltage change rate exhibits linearity in the range of −10 [mT] to 10 [mT].

  FIG. 10 is a diagram illustrating a relationship between hysteresis and temperature of the magnetoresistive elements according to the comparative example and the example. With reference to FIG. 10, the relationship between the hysteresis and temperature of the magnetoresistive element according to the comparative example and the example will be described.

  As shown in FIG. 10, in the magnetoresistive element in the comparative example, the hysteresis increases as the temperature decreases, and the hysteresis increases significantly on the low temperature side. On the other hand, in the magnetoresistive element according to the example, the hysteresis is small in the range of −40 ° C. to 125 ° C., and the magnitude of the hysteresis hardly changes.

  As described above, the magnetoresistive element according to the example has smaller hysteresis particularly on the low temperature side than the magnetoresistive element in the comparative example.

  As a result of the verification experiment described above, by providing the first ferromagnetic layer 16 between the antiferromagnetic layer 14 and the second ferromagnetic layer 15, It can be said that it was proved experimentally that the diffusion of Mn into the layer 15 can be suppressed.

  Further, it can be said that the provision of the first ferromagnetic layer 16 has proved experimentally that the linearly responding region can be expanded and the hysteresis on the low temperature side can be reduced.

(Embodiment 2)
FIG. 11 is a schematic cross-sectional view of the magnetoresistive element according to the present embodiment. A magnetoresistive element 1E according to the present exemplary embodiment will be described with reference to FIG.

  As shown in FIG. 11, the magnetoresistive element 1E according to the present embodiment does not include a barber pole electrode when compared with the magnetoresistive element 1 according to the first embodiment, and an antiferromagnetic material. The difference is that the magnetization direction of the first ferromagnetic layer 16 fixed by the exchange coupling magnetic field from the layer 14 and the magnetization direction of the second ferromagnetic layer 15 are different.

  FIG. 12 is a plan view showing the magnetization direction of the ferromagnetic layer fixed by the exchange coupling magnetic field from the antiferromagnetic layer and the direction connecting the electrodes at the shortest in the magnetoresistive element shown in FIG. is there. With reference to FIG. 12, the magnetization direction of the ferromagnetic layer fixed by the exchange coupling magnetic field from the antiferromagnetic layer and the direction connecting the electrode portions in the shortest will be described.

  As shown in FIG. 12, the magnetization direction of the second ferromagnetic layer 15 fixed by the exchange coupling magnetic field generated between the first ferromagnetic layer 16 and the antiferromagnetic layer 14 and the electrode portion 18 are It intersects with the direction connecting at the shortest. Specifically, the angle θ at which the magnetization direction of the second ferromagnetic layer 15 fixed by the exchange coupling magnetic field intersects the direction connecting the electrode portions 18 at the shortest is 45 degrees. The direction connecting the electrode portions 18 at the shortest coincides with the longitudinal direction of the laminate 12.

  Such a magnetoresistive element 1E is manufactured as follows. First, after forming from the underlayer 13 to the second ferromagnetic layer 15 using a vacuum deposition method, a sputtering method, or the like, heat treatment is performed while applying a magnetic field. Thus, an exchange coupling magnetic field is obtained between the first ferromagnetic layer 16 and the antiferromagnetic layer 14, and the magnetization directions of the first ferromagnetic layer 16 and the second ferromagnetic layer 15 are the directions of the magnetic fields. Fixed to.

  When the antiferromagnetic material layer 14 is a disordered alloy, it is formed from the underlayer 13 to the second ferromagnetic material layer 15 using a vacuum vapor deposition method, a sputtering method or the like while applying a magnetic field. The magnetization directions of the first ferromagnetic layer 16 and the second ferromagnetic layer 15 are fixed in the direction of the magnetic field by the exchange coupling magnetic field between the first ferromagnetic layer 16 and the antiferromagnetic layer 14. In this case, heat treatment for generating exchange coupling is not necessary.

  On the other hand, when the antiferromagnetic layer 14 is an ordered alloy, the first ferromagnetic layer 16 and the antiferromagnetic layer 14 are formed by performing a heat treatment while applying a magnetic field after forming the stacked body 12. An exchange coupling magnetic field is obtained between the first and second ferromagnetic layers 16 and 15, and the magnetization directions of the first and second ferromagnetic layers 16 and 15 are fixed to the direction of the magnetic field. In this case, the direction of the applied magnetic field is better to be the same direction as the magnetic field applied during formation.

  Subsequently, the laminated body 12 is formed by a photolithography method or the like so that the angle at which the magnetization direction of the second ferromagnetic layer 15 fixed by the exchange coupling magnetic field intersects the longitudinal direction of the laminated body 12 is 45 °. Patterned into a rectangular shape.

  In the present embodiment, most of the detection current I flowing from the electrode portion 18 on one end side toward the electrode portion 18 on the other end side flows in the direction connecting the pair of electrode portions 18 in the shortest distance. For this reason, when forming the laminated body 12, the direction of connecting the electrode parts 18 in the shortest and the magnetization direction of the second ferromagnetic layer 15 intersect with each other at 45 ° in advance. By fixing the magnetization direction, a good linearly responding region can be obtained.

  Also in the present embodiment, the first ferromagnetic layer 16 is provided between the antiferromagnetic layer 14 and the second ferromagnetic layer 15. Thereby, diffusion of Mn from the antiferromagnetic material layer 14 can be suppressed, and hysteresis under a low temperature environment can be reduced.

  In the present embodiment, the barber pole electrode is not provided on the second ferromagnetic layer 15, and the magnetization direction of the second ferromagnetic layer 15 is the direction in which the detection current flows (the distance between the electrodes is shortest). Can be fixed at an angle of 45 ° with respect to the connecting direction. Thereby, it can suppress that the magnetosensitive area | region of the 2nd ferromagnetic material layer 15 reduces.

  Further, since the barber pole electrode is not provided, it is possible to prevent the electric resistance of the barber pole electrode from being added to the electric resistance of the ferromagnetic layer. As a result, the magnetoresistive element 1E according to the present exemplary embodiment can suppress the decrease in the magnetosensitive region and improve the magnetoresistance change rate.

(Magnetic sensor)
FIG. 13 is a plan view of a magnetic sensor configured by using a plurality of magnetoresistive elements shown in FIG. With reference to FIG. 13, a magnetic sensor 100A configured using a plurality of magnetoresistive elements shown in FIG. 11 will be described.

  As shown in FIG. 13, when compared with the magnetic sensor 100 according to the first embodiment, the magnetic sensor 100A includes four magnetoresistive elements 1A, 1B, 1C, and 1D according to the second embodiment. 1E is different in that it is configured. Other configurations are substantially the same, and a full bridge circuit is formed by these four magnetoresistive elements 1A, 1B, 1C, and 1D.

  The magnetoresistive elements 1A, 1B, 1C, 1D are arranged so that the magnetization directions are aligned in a certain direction. The magnetoresistive elements 1A, 1B, 1C, and 1D are arranged so that the region surrounded by them is substantially square. The magnetoresistive elements 1A and 1B are arranged so as to be orthogonal to each other. The magnetoresistive elements 1C and 1D are arranged so as to be orthogonal to each other. The magnetoresistive elements 1A and 1C are arranged so that the directions connecting the electrodes at the shortest are parallel. The magnetoresistive elements 1B and 1D are arranged so that the directions connecting the electrodes at the shortest are parallel. The magnetoresistive elements 1A and 1C have a positive output property, and the magnetoresistive elements 1B and 1D have a negative output property.

  When the power supply voltage Vcc is applied between the electrode pad P3 and the electrode pad P4, output voltages Vout2 and Vout1 are extracted from the electrode pad P1 and the electrode pad P2 according to the magnetic field strength. The output voltages Vout2 and Vout1 are differentially amplified through a differential amplifier (not shown).

  With this configuration, Mn diffusion from the antiferromagnetic material layer 14 to the second ferromagnetic material layer 15 is suppressed during the manufacture of the magnetoresistive element and the magnetic sensor, thereby reducing hysteresis even in a low temperature environment. Can be made.

  Further, in the magnetic sensor according to the present embodiment, since the barber pole electrode is not provided on the magnetoresistive element, the processing variation of the barber pole electrode does not occur. For this reason, variation in electric resistance of the magnetoresistive element is small, and when a full bridge circuit is configured, the offset voltage can be easily adjusted.

(Modification of magnetic sensor)
FIG. 14 is a plan view showing a modification of the magnetic sensor shown in FIG. A modification of the magnetic sensor will be described with reference to FIG.

  When compared with the magnetic sensor 100A according to the second embodiment, the magnetic sensor 100B according to the modified example includes the magnetoresistive elements 1A, 1B, 1C, and 1D in which a plurality of stacked bodies 12 are arranged in a meander shape. It is different in that it is configured by being connected to each other.

  Specifically, as shown in FIG. 14, a plurality of laminated bodies 12 are provided in each of the magnetoresistive elements 1A, 1B, 1C, and 1D. Each magnetoresistive element 1 </ b> A, 1 </ b> B, 1 </ b> C, 1 </ b> D further includes a plurality of connection electrodes 40. In each of the magnetoresistive elements 1A, 1B, 1C, and 1D, the plurality of stacked bodies 12 are provided in parallel so that the magnetization directions are aligned. The connection electrodes 40 as the electrode portions alternately connect the end portions of the stacked bodies 12 adjacent to each other. Thereby, each magnetoresistive element 1A, 1B, 1C, 1D is formed in the meander shape.

  More specifically, each of the magnetoresistive elements 1A, 1B, 1C, and 1D is formed by connecting the stacked body 12 having a long strip pattern and the connection electrodes 40 having a short strip pattern alternately and orthogonally, It is formed in a meander shape.

  Each of the plurality of stacked bodies 12 included in the magnetoresistive elements 1A and 1C extends along the same direction, and is arranged at a predetermined interval in a direction orthogonal to the extending direction. Each of the plurality of stacked bodies 12 included in the magnetoresistive elements 1B and 1D extends along the same direction, and is arranged at a predetermined interval in a direction orthogonal to the extending direction. The extending direction of the multiple stacked bodies 12 included in the magnetoresistive elements 1A and 1C is orthogonal to the extending direction of the multiple stacked bodies 12 included in the magnetoresistive elements 1B and 1D.

  Even in this case, since Mn diffusion from the antiferromagnetic material layer to the second ferromagnetic material layer 15 is suppressed during the manufacture of the magnetoresistive element and the magnetic sensor, hysteresis is maintained even in a low temperature environment. Can be reduced. Further, since the barber pole electrode is not provided, it is easy to adjust the offset voltage.

(Embodiment 3)
(Current sensor)
FIG. 15 is a schematic diagram showing a current sensor according to the present embodiment. A current sensor according to the present embodiment will be described with reference to FIG.

  As shown in FIG. 15, a current sensor 150 according to the present embodiment includes magnetic sensors 100C and 100D, a bus bar 110 through which a current to be measured flows, and a subtractor 130. The magnetic sensors 100C and 100D have the same configuration as that of the magnetic sensor 100 according to Embodiment 1, and have an odd function input / output characteristic. The magnetic sensors 100C and 100D detect the strength of the magnetic field generated by the current flowing through the bus bar 110, and output a signal corresponding to the strength of the magnetic field from the bridge circuit. The subtractor 130 is a calculation unit that calculates the current value by subtracting the detection values of the magnetic sensor 100C and the magnetic sensor 100D.

  Bus bar 110 includes a first bus bar portion 111, a second bus bar portion, and a third bus bar portion 113 that are electrically connected in series. The first bus bar portion 111 and the third bus bar portion 113 are spaced apart from each other and extend in parallel. The first bus bar portion 111 and the third bus bar portion 113 are connected by the second bus bar portion.

  The second bus bar portion includes a parallel portion 112 extending in parallel with an interval from each of the first bus bar portion 111 and the third bus bar portion 113. The second bus bar portion includes a first connecting portion 114 that connects the other end of the first bus bar portion 111 and one end of the parallel portion 112 of the second bus bar portion, and the other end of the parallel portion 112 of the second bus bar portion. 2nd connection part 115 which connects the one end of the 3rd bus-bar part 113 is included.

  The first bus bar part 111, the parallel part 112 of the second bus bar part, and the third bus bar part 113 are arranged at equal intervals. Each of the first bus bar portion 111, the parallel portion 112 of the second bus bar portion, and the third bus bar portion 113 has a rectangular parallelepiped shape. However, the shape of each of the first bus bar portion 111, the parallel portion 112 of the second bus bar portion, and the third bus bar portion 113 is not limited to a rectangular parallelepiped shape, and may be, for example, a cylindrical shape.

  The first connecting portion 114 of the second bus bar portion extends linearly in a side view and is orthogonal to each of the first bus bar portion 111 and the parallel portion 112 of the second bus bar portion. The second connecting portion 115 of the second bus bar portion extends linearly in a side view and is orthogonal to each of the parallel portion 112 and the third bus bar portion 113 of the second bus bar portion.

  Each of the 1st connection part 114 and the 2nd connection part 115 of a 2nd bus-bar part has a rectangular parallelepiped shape. However, each shape of the 1st connection part 114 of the 2nd bus-bar part and the 2nd connection part 115 is not restricted to a rectangular parallelepiped shape, For example, a column shape may be sufficient.

  Bus bar 110 has an S-shape when viewed from the side. By configuring the bus bar 110 with one bus bar member having a bent shape so as to be folded back, the bus bar 110 having a high mechanical strength and a symmetrical shape can be obtained. However, the shape of the bus bar 110 is not limited to this. For example, the bus bar 110 is appropriately selected as long as the bus bar 110 has a shape including the first bus bar portion 111, the second bus bar portion, and the third bus bar portion 113 such as an E shape. be able to.

  Bus bar 110 is made of aluminum, for example. However, the material of the bus bar 110 is not limited to this, and may be a single metal such as silver or copper, or an alloy of these metals and other metals. The bus bar 110 may be subjected to a surface treatment. For example, a plating layer made of a single metal such as nickel, tin, silver, copper, or an alloy thereof may be formed on the surface of the bus bar 110 as a single layer or multiple layers.

  The bus bar 110 is formed by pressing a thin plate. However, the method of forming the bus bar 110 is not limited to this, and the bus bar 110 may be formed by a method such as cutting, casting, or forging.

  A direction 211 in which current flows through the first bus bar portion 111 and a direction 215 in which current flows through the third bus bar portion 113 are the same. The direction 211 in which current flows in the first bus bar part 111, the direction 215 in which current flows in the third bus bar part 113, and the direction 213 in which current flows in the parallel part 112 of the second bus bar part 113 are opposite. The direction 212 in which the current flows through the first connecting portion 114 of the second bus bar portion is the same as the direction 214 in which the current flows through the second connecting portion 115 of the second bus bar portion.

  The magnetic sensor 100C is located between the first bus bar portion 111 and the parallel portion 112 of the second bus bar portion facing each other. The magnetic sensor 100D is located between the parallel portion 112 and the third bus bar portion 113 of the second bus bar portion facing each other.

  The magnetic sensor 100C is in a direction orthogonal to the direction in which the first bus bar portion 111 and the third bus bar portion 113 are arranged, and in a direction orthogonal to the extending direction of the first bus bar portion 111 in FIG. The detection axis is in the direction indicated by the arrow 101A.

  The magnetic sensor 100D is in a direction orthogonal to the direction in which the first bus bar part 111 and the third bus bar part 113 are arranged, and in a direction orthogonal to the extending direction of the third bus bar part 113 in FIG. And has a detection axis in the direction indicated by arrow 101B.

  The magnetic sensors 100C and 100D output a positive value when a magnetic field directed in one direction of the detection axis is detected, and are negative when a magnetic field directed in a direction opposite to the one direction of the detection axis is detected. It has an odd function input / output characteristic that outputs a value. That is, with respect to the strength of the magnetic field generated by the current flowing through the bus bar 110, the phase of the detection value of the magnetic sensor 100C is opposite to the phase of the detection value of the magnetic sensor 100D.

  The magnetic sensor 100 </ b> C is electrically connected to the subtractor 130 through the first connection wiring 141. The magnetic sensor 100 </ b> D is electrically connected to the subtractor 130 by the second connection wiring 142.

  The subtractor 130 calculates the value of the current flowing through the bus bar 110 by subtracting the detection value of the magnetic sensor 100C and the detection value of the magnetic sensor 100D. In the present embodiment, the subtractor 130 is used as the calculation unit. However, the calculation unit is not limited to this, and a differential amplifier or the like may be used.

  FIG. 16 is a diagram schematically showing a generated magnetic field in the cross-sectional view seen from the direction of the arrow XVI-XVI shown in FIG. In FIG. 16, the detection axis direction of the magnetic sensor 100C and the magnetic sensor 100D is shown as the X direction, and the direction in which the first bus bar part 111, the parallel part 112 of the second bus bar part and the third bus bar part 113 are arranged is shown as the Y direction. Yes. The extending direction of the parallel portion 112 of the second bus bar portion is the Z direction.

  As shown in FIG. 16, when a current flows through the first bus bar portion 111, a magnetic field 111 e that circulates clockwise in the drawing according to a so-called right-handed screw law is generated. Similarly, when a current flows through the parallel portion 112 of the second bus bar portion, a magnetic field 112e that circulates counterclockwise in the figure is generated. When a current flows through the third bus bar portion 113, a magnetic field 113e that circulates clockwise in the figure is generated.

  As a result, a leftward magnetic field in the figure is applied to the magnetic sensor 100C in the direction of the detection axis indicated by the arrow 101A. On the other hand, a rightward magnetic field in the figure is applied to the magnetic sensor 100D in the direction of the detection axis indicated by the arrow 101B.

  Therefore, if the magnetic field intensity detected by the magnetic sensor 100C is a positive value, the magnetic field intensity detected by the magnetic sensor 100D is a negative value. The detection value of the magnetic sensor 100C and the detection value of the magnetic sensor 100D are transmitted to the subtractor 130.

  The subtractor 130 subtracts the detection value of the magnetic sensor 100D from the detection value of the magnetic sensor 100C. As a result, the absolute value of the detection value of the magnetic sensor 100C and the absolute value of the detection value of the magnetic sensor 100D are added. From the addition result, the value of the current flowing through the bus bar 110 is calculated.

  Note that an adder or an addition amplifier may be used as the calculation unit in place of the subtractor 130 while the input / output characteristics of the magnetic sensor 100C and the magnetic sensor 100D have opposite polarities.

  In the current sensor 150 in the present embodiment, the first bus bar portion 111 and the third bus bar portion 113 are positioned symmetrically with respect to each other about the center point of the parallel portion 112 of the second bus bar portion in the cross section. In addition, the first bus bar portion 111 and the third bus bar portion 113 are positioned symmetrically with respect to each other about the center line of the parallel portion 112 of the second bus bar portion in the direction of the detection axis of the magnetic sensor 100C and the magnetic sensor 100D in the cross section. doing.

  Further, the magnetic sensor 100C and the magnetic sensor 100D are located point-symmetrically with respect to the center point of the parallel portion 112 of the second bus bar portion in the cross section. In addition, the magnetic sensor 100C and the magnetic sensor 100D are positioned symmetrically with respect to each other about the center line of the parallel portion 112 of the second bus bar portion in the direction of the detection axis of the magnetic sensor 100C and the magnetic sensor 100D in the cross section.

  The magnetic sensor 100C and the magnetic sensor 100D that are arranged point-symmetrically in this way show detection values that equally reflect the magnetic field generated by the current flowing through the bus bar 110. Therefore, the linearity between the strength of the magnetic field generated by the current flowing through the bus bar 110 and the value of the current flowing through the bus bar 110 calculated therefrom can be improved.

  In the present embodiment, the case where the magnetic sensors 100C and 100D included in the current sensor 150 are configured by the magnetoresistive element according to the first embodiment has been described, but the present invention is not limited thereto. The magnetoresistive element according to the second embodiment and the magnetoresistive element according to a fourth embodiment described later may be used. Further, as the magnetic sensors 100C and 100D, a magnetic sensor 100H1 according to a fifth embodiment to be described later or a magnetic sensor 100H2 according to an embodiment to be described later may be used.

  With the configuration as described above, the current sensor 150 according to the present embodiment suppresses the Mn diffusion from the antiferromagnetic material layer to the second ferromagnetic material layer 15, thereby reducing hysteresis even in a low temperature environment. Can be made.

(Embodiment 4)
(Magnetic resistance element)
FIG. 17 is a schematic cross-sectional view of the magnetoresistive element according to the present embodiment. A magnetoresistive element 1F according to the present exemplary embodiment will be described with reference to FIG.

  As illustrated in FIG. 17, the magnetoresistive element 1 </ b> F according to the present embodiment is different from the magnetoresistive element 1 according to the first embodiment in the configuration of the stacked body 12 </ b> F. Other configurations are almost the same.

  The stacked body 12F is configured by stacking an underlayer 13, a second ferromagnetic layer 15, a first ferromagnetic layer 16, and an antiferromagnetic layer 14 in this order from the substrate 10 side.

  The underlayer 13 is provided on the insulating layer 11. The underlayer 13 is provided for appropriately growing the crystals of the second ferromagnetic layer 15, the first ferromagnetic layer 16, and the antiferromagnetic layer 14. The underlayer 13 is omitted when the second ferromagnetic layer 15, the first ferromagnetic layer 16 crystal and the antiferromagnetic layer 14 can be appropriately grown without using this. Can do. When the underlayer 13 is omitted, the configuration of the magnetoresistive element 1 can be simplified.

  The second ferromagnetic layer 15 is provided above the substrate 10. Specifically, the second ferromagnetic layer 15 is provided on the underlayer 13. The first ferromagnetic layer 16 is provided on the second ferromagnetic layer 15 so as to cover the entire main surface of the second ferromagnetic layer 15 located on the side opposite to the side on which the substrate 10 is located. . The first ferromagnetic layer 16 is provided between the second ferromagnetic layer 15 and the antiferromagnetic layer 14.

  The first ferromagnetic layer 16 and the second ferromagnetic layer 15 function as an underlayer for appropriately growing the crystal of the antiferromagnetic layer 14. The antiferromagnetic material layer 14 is provided on the first ferromagnetic material layer 16 so as to cover the entire main surface of the first ferromagnetic material layer 16 located on the side opposite to the side on which the substrate 10 is located.

  Also in this case, the magnetization directions of the first ferromagnetic layer 16 and the second ferromagnetic layer 15 are fixed in a predetermined direction by the exchange coupling magnetic field acting from the antiferromagnetic layer 14. For example, the magnetization directions of the first ferromagnetic layer 16 and the second ferromagnetic layer 15 are fixed in the longitudinal direction of the stacked body 12F.

  The plurality of barber pole electrodes 17 are provided above the stacked body 12. Specifically, the plurality of barber pole electrodes 17 are provided on the antiferromagnetic material layer 14 so as to be separated from each other. The plurality of barber pole electrodes 17 are provided so as to be inclined by 45 ° with respect to the longitudinal direction of the laminate 12. By providing the barber pole electrode 17, the direction of the detection current flowing through the second ferromagnetic layer 20 can be reliably tilted in a direction that connects the adjacent barber pole electrodes 17 in the shortest distance. In order to improve the adhesion between the barber pole electrode 17 and the antiferromagnetic layer 14, an adhesion layer made of Ti or the like may be provided between the barber pole electrode 17 and the antiferromagnetic layer 14. .

  Also in the present embodiment, by providing the first ferromagnetic layer 16 made of Co or an alloy containing Co between the second ferromagnetic layer and the antiferromagnetic layer, during the heat treatment in the manufacturing process, Mn contained in the antiferromagnetic material layer 14 can be prevented from diffusing into the second ferromagnetic material layer 15. Thereby, even when a magnetoresistive element is used in a low temperature environment, a hysteresis can be reduced.

  In the present embodiment, the case where the barber pole electrode 17 is provided has been described as an example. However, the present invention is not limited to this, and the longitudinal direction of the stacked body 12 is changed by the exchange coupling magnetic field acting from the antiferromagnetic material layer 14. On the other hand, when the magnetization directions of the first ferromagnetic layer 16 and the second ferromagnetic layer 15 are fixed in a direction intersecting at an angle of approximately 45 degrees with respect to the barber pole electrode 17 as in the second embodiment. Can be omitted.

(Embodiment 5)
(Magnetic sensor)
FIG. 18 is a plan view of the magnetic sensor according to the present embodiment. A magnetic sensor 100H1 according to the present embodiment will be described with reference to FIG.

  As shown in FIG. 18, the magnetic sensor 100H1 according to the present embodiment is provided by configuring a full bridge circuit using four magnetoresistive elements 1H1, 1H2, 1H3, and 1H4.

  The magnetoresistive elements 1H1, 1H2, 1H3, and 1H4 basically have a configuration according to the magnetoresistive element 1E according to the second embodiment. The magnetoresistive elements 1H1, 1H2, 1H3, and 1H4 are laminated bodies 12H1, 12H2 included in the magnetoresistive elements 1H1, 1H2, 1H3, and 1H4, as will be described later, when compared with the magnetoresistive element 1E according to the second embodiment. , 12H3, 12H4 are different in shape.

  A wiring pattern 3A and an electrode pad P1 for taking out the output voltage Vout2 are formed on one end side of the magnetoresistive element 1H1. A wiring pattern 3B and an electrode pad P3 for applying the power supply voltage Vcc are formed on the other end side of the magnetoresistive element 1H1.

  A wiring pattern 3A and an electrode pad P1 are formed on one end side of the magnetoresistive element 1H4. On the other end side of the magnetoresistive element 1H4, a wiring pattern 3D and an electrode pad P4 connected to the ground are formed.

  A wiring pattern 3C and an electrode pad P2 for taking out the output voltage Vout1 are formed on one end side of the magnetoresistive element 1H2. A wiring pattern 3B and an electrode pad P3 are formed on the other end side of the magnetoresistive element 1H2.

  A wiring pattern 3C and an electrode pad P2 are formed on one end side of the magnetoresistive element 1H3. A wiring pattern 3D and an electrode pad P4 are formed on the other end side of the magnetoresistive element 1H3.

  In the magnetic sensor 100H1, the magnetoresistive elements 1H1 and 1H3 have positive output characteristics, and the magnetoresistive elements 1H2 and 1H4 have negative output characteristics. When the power supply voltage Vcc is applied between the electrode pad P3 and the electrode pad P4, output voltages Vout2 and Vout1 are extracted from the electrode pad P1 and the electrode pad P2 according to the magnetic field strength. The output voltages Vout2 and Vout1 are differentially amplified through a differential amplifier (not shown).

  The stacked bodies 12H1, 12H2, 12H3, and 12H4 have a portion 21 that is formed in a meander shape so that the magnetization directions are aligned, and electrode base portions 22 that are connected to both ends of the portion 21 that is formed in a meander shape. .

  The portion 21 formed in a meander shape includes a plurality of linear portions 21a arranged in parallel and a plurality of folded portions 21b that alternately connect the ends of the adjacent linear portions 21a.

  In the magnetoresistive elements 1H1 and 1H3, the plurality of linear portions 21a included in the stacked body 12 extend along the same direction. In the magnetoresistive elements 1H2 and 1H4, the plurality of linear portions 21a included in the stacked body 12 extend in the same direction.

  The extending direction of the linear portion 21a included in the magnetoresistive elements 1H1 and 1H3 is orthogonal to the extending direction of the linear portion 21a included in the magnetoresistive elements 1H2 and 1H4.

  The laminated bodies 12H1, 12H2, 12H3, and 12H4 are integrally formed by patterning a laminated film in which the magnetization direction of the ferromagnetic film that becomes the ferromagnetic layer 20 is fixed in a predetermined direction by an exchange coupling magnetic field. ing.

  As in the first embodiment, the multilayer film includes a base film that becomes the base layer 13, an antiferromagnetic film that becomes the antiferromagnetic layer 14, and a first ferromagnetic layer using vacuum deposition, sputtering, or the like. The first ferromagnetic film to be 16 and the second ferromagnetic film to be the second ferromagnetic layer 15 are stacked. As in the first embodiment, the first ferromagnetic film and the laminated film are formed by applying a magnetic field, or by heat treatment while applying the magnetic field to the laminated film after forming the laminated film. The magnetization directions of the first ferromagnetic film and the second ferromagnetic film are fixed by the exchange coupling magnetic field generated between the second ferromagnetic film and the antiferromagnetic film.

  The magnetoresistive element 1H1 and the magnetoresistive element 1H2 have a common electrode base 22. On the common electrode base 22 of the magnetoresistive element 1H1 and the magnetoresistive element 1H2, a wiring pattern 3B and an electrode pad P3 for applying the power supply voltage Vcc are formed.

  The magnetoresistive element 1H2 and the magnetoresistive element 1H3 have a common electrode base 22. On the common electrode base 22 of the magnetoresistive element 1H2 and the magnetoresistive element 1H3, an electrode pad P2 for taking out the wiring pattern 3C and the output voltage Vout1 is formed.

  The magnetoresistive element 1H3 and the magnetoresistive element 1H4 have a common electrode base 22. An electrode pad P4 connected to the wiring pattern 3D and the ground is formed on the common electrode base 22 of the magnetoresistive element 1H3 and the magnetoresistive element 1H4.

  The magnetoresistive element 1H4 and the magnetoresistive element 1H1 have a common electrode base 22. On the common electrode base 22 of the magnetoresistive element 1H4 and the magnetoresistive element 1H1, an electrode pad P1 for taking out the wiring pattern 3A and the output voltage Vout2 is formed.

  Even in such a configuration, when the magnetoresistive element and the magnetic sensor are manufactured, the first ferromagnetic layer 16 made of Co or an alloy containing Co is used as the antiferromagnetic layer and the second ferromagnetic layer. Since the Mn diffusion from the antiferromagnetic material layer 15 to the second ferromagnetic material layer 15 is suppressed, the hysteresis can be reduced even in a low temperature environment. Further, since the barber pole electrode is not provided, it is easy to adjust the offset voltage.

  Further, by providing the electrode base portion 22 and forming the wiring patterns 3A, 3B, 3C, 3D and the electrode pads P1, P2, P3, P4 on the electrode base portion 22, the wiring pattern 3A and the electrode pad P1, the wiring It is possible to prevent a step from being formed in each of the pattern 3B and the electrode pad P3, the wiring pattern 3C and the electrode pad P2, and the wiring pattern 3D and the electrode pad 4.

  As a result, the wiring patterns 3A, 3B, 3C, 3D and the electrode pads P1, P2, P3, P4 can be prevented from being disconnected, and the reliability can be improved.

(Embodiment 6)
(Magnetic sensor)
FIG. 19 is a plan view of the magnetic sensor according to the present embodiment. A magnetic sensor 100H2 according to the present embodiment will be described with reference to FIG.

  As shown in FIG. 19, when compared with the magnetic sensor 100H1 according to the fifth embodiment, the magnetic sensor 100H2 according to the present embodiment has more than the ferromagnetic layer 20 on each of the plurality of folded portions 21b. The difference is that a conductive layer 44 having a low electrical resistance is provided. Other configurations are almost the same.

  In each of the magnetoresistive elements 1H1, 1H2, 1H3, and 1H4, when the conductive layer 44 is not provided, in the stacked bodies 12H1, 12H2, 12H3, and 12H4, a ferromagnetic layer positioned in the linear portion 21a; A current flows through both of the ferromagnetic layers located in the folded portion 21b.

  The direction of the current flowing through the ferromagnetic layer positioned at the linear portion 21a is orthogonal to the direction of the current flowing through the ferromagnetic layer positioned at the folded portion 21b. For this reason, when an electric current flows through the ferromagnetic layer located in the folded portion 21b, a part of the output generated from the ferromagnetic layer located in the linear portion 21a is strong in the folded portion 21b. It is canceled out by the output generated from the magnetic layer. As a result, the extracted output voltages Vout2 and Vout1 may decrease.

  In the present embodiment, the folded portion is provided by providing the conductive layer 44 having a lower electrical resistance than the ferromagnetic layer on the folded portion 21b (more specifically, on the ferromagnetic layer positioned at the folded portion 21b). In 21b, the current flows through the conductive layer 44. For this reason, it is possible to prevent a part of the output generated from the ferromagnetic layer 20 positioned in the linear portion 21a from being canceled by the output generated from the ferromagnetic layer positioned in the folded portion 21b. .

  In the magnetic sensors 100H1 and 100H2 according to the fifth and sixth embodiments described above, the magnetoresistive elements 1H1, 1H2, 1H3, and 1H4 basically have a configuration according to the magnetoresistive element 1E according to the second embodiment. However, the present invention is not limited to this, and may have a configuration according to the magnetoresistive elements according to the first and fourth embodiments.

  Although the embodiments and examples of the present invention have been described above, the embodiments and examples disclosed this time are illustrative and not restrictive in all respects. The scope of the present invention is defined by the terms of the claims, and includes meanings equivalent to the terms of the claims and all changes within the scope.

  1, 1A, 1B, 1C, 1D, 1E, 1F, 1H1, 1H2, 1H3, 1H4 Magnetoresistive element, 3A, 3B, 3C, 3D wiring pattern, 10 substrate, 11 insulating layer, 12, 12F, 12H1, 12H2, 12H3, 12H4 laminate, 13 underlayer, 14 antiferromagnetic layer, 15 second ferromagnetic layer, 16 first ferromagnetic layer, 17 barber pole electrode, 18 electrode section, 19 protective layer, 19a contact hole, 20 ferromagnetic layer, 21 meander-shaped portion, 21a linear portion, 21b folded portion, 22 electrode base portion, 40 connection electrode, 44 conductive layer, 100, 100A, 100B, 100C, 100D, 100H1, 100H2 magnetic sensor, 110 busbar, 111 first busbar section, 111e, 112e, 113e magnetic field, 112 flat Department, 113 third bus bar portions, 114 a first connecting portion, 115 a second connecting portion, 130 a subtracter, 141 first connection wiring, 142 a second connection wiring, 150 a current sensor.

Claims (12)

A substrate,
A laminated body provided above the substrate and laminated with an antiferromagnetic layer and a ferromagnetic layer;
The ferromagnetic layer includes a first ferromagnetic layer made of Co or an alloy containing Co, and a second ferromagnetic layer made of an alloy containing Ni and Fe,
The antiferromagnetic material layer is made of an alloy containing Mn,
The first ferromagnetic layer is provided between the antiferromagnetic layer and the second ferromagnetic layer;
A magnetoresistive element, wherein the first ferromagnetic layer and the antiferromagnetic layer are exchange coupled.   2. The magnetic layer according to claim 1, wherein the stacked body is configured by stacking the second ferromagnetic layer, the first ferromagnetic layer, and the antiferromagnetic layer in order from the substrate side. Resistance element.   2. The magnetic layer according to claim 1, wherein the stacked body is configured by stacking the antiferromagnetic layer, the first ferromagnetic layer, and the second ferromagnetic layer sequentially from the substrate side. Resistance element. The second ferromagnetic layer is provided so as to cover the entire first ferromagnetic layer when viewed from the stacking direction of the stacked body,
4. The magnetoresistive element according to claim 1, further comprising a plurality of barber pole electrodes that are spaced apart from each other and provided above the stacked body. 5. Further comprising electrode portions provided at both ends of the laminate,
The magnetization direction of the first ferromagnetic layer fixed by the exchange coupling magnetic field generated between the first ferromagnetic layer and the antiferromagnetic layer intersects with the direction connecting the electrodes in the shortest distance. The magnetoresistive element according to any one of claims 1 to 3.   6. The magnetoresistive element according to claim 5, wherein an angle at which the magnetization direction of the first ferromagnetic layer fixed by the exchange coupling magnetic field intersects the direction connecting the electrode portions at the shortest is 45 degrees. .   The antiferromagnetic material layer includes an alloy containing any one of Ni, Fe, Pd, Pt, and Ir and Mn, an alloy containing Pd, Pt, and Mn, or Cr, Pt, and Mn. The magnetoresistive element of any one of Claim 1 to 6 which consists of an alloy containing. A plurality of connection electrode portions;
A plurality of the laminates are provided,
A plurality of the stacked bodies are provided in parallel so that the magnetization directions are aligned, and a plurality of the connection electrode portions are formed in a meander shape by alternately connecting the end portions of the stacked bodies adjacent to each other. The magnetoresistive element according to any one of claims 1 to 7.   The magnetoresistive element according to any one of claims 1 to 7, wherein the stacked body includes a portion formed in a meander shape so that the magnetization directions are aligned. The portion formed in the meander shape is constituted by a plurality of linear portions arranged in parallel and a plurality of folded portions that alternately connect the ends of the linear portions adjacent to each other.
The magnetoresistive element according to claim 9, wherein a conductive layer having an electric resistance lower than that of the ferromagnetic layer is provided on each of the plurality of folded portions.   A magnetic sensor comprising the magnetoresistive element according to claim 1. A bus bar through which the current to be measured flows,
A current sensor comprising: the magnetic sensor according to claim 11.

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